Process for preparing desacetoxycephalosporanic acids from cephalosporanic acids

ABSTRACT

A PROCESS FOR THE PREPARATION OF DESACETOXYCEPHALOSPORANIC ACIDS WITH PALLADIUM OXIDE HYDRATE OPTIONALLY SUPPORTED ON AN INERT CARRIER AND PALLADIUM OXIDE HYDRATE SUPPORTED ON ALPHA-CELLULOSE WHICH IS USEFUL IN THE PROCESS.

3,773,761 Patented Nov.-20, 1973 UnitedStates Patent Qflice ABSTRACT OF THEDISCLOSURE A'process for'the preparation of' desacetoxycephalosporanic acids with palladium oxide hydrate optionally supported on an inert carrier andpalladium oxide bydrate supported on alpha-cellulose which is useful in the process.

This invention relates to an improved process for the preparation of desacetoxycephalosporanic acids which comprises hydrogenating cephalo spor'anic acids with palladium oxide hydrate optionally supported on an inert carrier. Palladium oxide hydrate may be used in the process of this invention either unsupported or supported .on an inert carrier such as cellulose, carbon, calcium car: bonate or alumina.

In the process of this invention it is particularly advantageous to use palladium oxide hydrate supported on alpha-cellulose having a particle size of about 20 to 60 microns in average length and about 16 to 20 microns in average thickness. This material is also an object of this invention. n p

The process ofconverting cephalosporanic acids to desacetoxyccphalosporanic acids by hydrogenation is knownto the art. According to the method of Stedman, U.S. Pat. No. 3,124,576, hydrogenation is carried out using palladium-on-an-inert carrier such as palladiumon-carbon or palladium-on-barium sulfate.

The method of the present inven o n usmg palladium oxidehydrate optionally supported on an inert carrier is advantageous because consistent high yieldsof the desacetoxycephalosporanic acids are obtained. b

The process of this invention may be represented as follows:

' min i wcllzjo-lc-( llh V I v I N CH3 OH V p .acetoxycephalosporanic acid (cephalhexin), may be prepared by the process of this invention by hydrogenating the corresponding 7-acylaminocephalosporanic acids, for example 7-(D-a-aminophenylacetamido)cephalosporanic acid.

In the hydrogenation process according to this invention, the cephalosporauic acid and the palladium oxide hydrate optionally substituted on an inert carrier are present in a molar ratio of about 5.5 :l to 1:1. The process is carried out in an inert solvent, preferably water. Preferably, about 3 to 8 equivalents of base, such as ammonium carbonate, are present. The reaction mixture is preferably buffered at pH of about 7 to 9.5. A basic bulier such as sodium bicarbonate, sodium borate, ammonium chloride-ammonium hydroxide, ammonium bicarbonate or, preferably, ammonium carbonate is used. The hydrogenation is preferably carried out at about -5 C. to 15 C.

The palladium oxide hydrate used in the process of this invention is prepared by treating palladium chloride suspended in water with a base, for example a hydroxide such as sodium hydroxide, potassium hydroxide or lithium hydroxide or a carbonate such as ammonium carbonate or an alkali metal carbonate. To prepare the palladium oxide hydrate supported on an inert carrier, such as cellulose, carbon, calcium carbonate or alumina, the carrier is added to a suspension of palladium chloride in water and then alkali is added.

' Thefollowing examples are not limitingbut are illustrative of this invention.

EXAMPLE 1 Palladium chloride (62 g.) is suspended in.l.2 l. of deionized water and thefsuspension is heatedto C. with vigorous agitation. The aqueous suspension turns dark red. After five minutes, a solution of 40 g. of sodium hydroxide in 160 ml. of water is slowly added. The resultant brown suspension thickens slightly. The heating'is discontinued and the suspension is agitated until it is at room temperature (3-4 hours). The solid material is filtered off. When the filter cake is nearly dry, it is washed with 0.5 l. of water and 2 l. of 1% acetic acid, then air-dried overnight and then ground to give palladiumoxide hydrate. i

EXAMPLE 2 An autoclave is chilled to 4 C. and charged with 300 g. of ammonium carbonate, 272 g. of 7-'aminocephalosporanic acid,"2.4 l. of an equal mixture of tap water and ice and 29 g. of palladium 'oxidehydrate (prepared as in Example 1). The reaction is sealed and agitated for 15 minutes at 1 C., then flushed with hydrogen and then pressurized with 50 p'.s.il 'of' hydrogen. The reaction is agitated and the hydrogenolysisis allowed to proceed for 1.5 hours. I

The reaction mixture is acidified with 1.65 kg. of 50% (w./w.) cold sulfuric acid with cooling by adding ice to keep the temperature less than 10 C. Using suitable venting, 225 ml. of 22% ammonium sulfide is added. Charcoal is added-and the-suspension isfiltered. The filter cake is washed-with one literofZ N sulfuric acid; The filtrate is chilled'to5 C. and ammonium hydroxide is added slowly with agitation to bring the pH to 3.6. The suspension is cooled to 5 C. and allowed to stand for one hour.-The crystalline product is filtered off and washed with ml. of deionized waterandtwo 100 ml. por- I tions of acetone to give 7-aminodesacetoxycephalosporanic acid, yield 78-79%.

EXAMPLE 3 A suspension of palladium chloride (135.5 g.) in one gallon of deionized water is heated with agitation to 80 C. and maintained at this temperature for about 30 minutes. Alpha-cellulose (Solka-fioc BW-lOO) having a particle size of about 55 microns in average length and about 19 microns in average thickness (325 g.) is added and the suspension is agitated until the cellulose is wet. Then 166 ml. of 10 N sodium hydroxide is added within 10 minutes and the heating is discontinued. The suspension is allowed to cool to 40 C. The solid material is filtered ofi and washed with one gallon of 1% acetic acid to give palladium oxide hydrate supported on alpha-cellulose having a particle size of about 55 microns in average length and about 19 microns in average thickness (20% palladium by weight).

EXAMPLE 4 An autoclave is chilled to 4 C. and charged with 989 g. of ammonium carbonate, 833 g. of 7-aminocephalosporanic acid, 81.2 g. of palladium oxide hydrate supported on alpha-cellulose having a particle size of about 55 microns in average length and about 19 microns in average thickness (20% palladium by weight), prepared as in Example 3, and deionized water to bring the total volume to 15.14 liters. The reactor is sealed and agitated for 15 minutes at 1 C., then flushed with hydrogen and pressurized with 50 p.s.i. of hydrogen. The agitation is again initiated and the hydrogenolysis is allowed to proceed for 1.5 hours.

The reaction mixture is acidified with 5.28 kg. of 50% (w./w.) cold sulfuric acid with cooling by adding ice to keep the temperature less than 10 C. Using suitable venting, 742.5 ml. of 22% ammonium sulfide is added. Approximately 400 g. of cellulose is added and the suspension is filtered. The filter cake is washed with 3.3 l. of l 2 N sulfuric acid. The filtrate is chilled to 5 C. and ammonium hydroxide is added with agitation to bring the pH to 3.6. The suspension is cooled to 5 C. and allowed to stand for one hour. The crystalline product is cooled and washed with 300 ml. of deionized water and two 300 ml. portions of acetone to give 7-aminodesacetoxycephalosporanic acid, yield 79-86%.

EXAMPLE 5 A suspension of 62 g. of palladium chloride in 1.2 l. of deionized water is heated with agitation at 80 C. for five minutes. Carbon is added and the suspension is agitated until the carbon is wet. Then a solution of 40 g. of sodium hydroxide in 160 ml. of water is slowly added. The heating is discontinued and the agitation is continued for three hours. Filtering and washing the filter cake with 1% acetic acid gives 10% palladium oxide hydrate supported on carbon.

Hydrogenolysis of 7-aminocephalosporanic acid (204 g.) using the above prepared 10% palladium oxide hydrate supported on carbon (220 g.) by the procedure of Example 4 gives 7-aminodesacetoxycephalosporanic acid.

EXAMPLE 6 By the procedure of Example 2, cephalosporin C is hydrogenated using palladium oxide hydrate (prepared as in Example 1) to give 7-(5-aminoadipamido)desacetoxycephalosporanic 'acid.

EXAMPLE 7 By the procedure of Example 4, 7-(D-u-aminophenylacetamido)cephalosporanic acid is hydrogenated using palladium oxide hydrate supported on alpha-cellulose having a particle size of about 55 microns in average length and about 19 microns in average thickness (20% palladium by weight), prepared as in Example 3, to give 7- (D-a-aminophenylacetamido )desacetoxycephalosporanic acid.

4 EXAMPLE 8 By the procedure of Example 4, the following cephalosporanic acids are hydrogenated using palladium oxide hydrate supported on alpha-cellulose (prepared as in Example 3):

7-mandelamidocephalosporanic acid 7-phenylacetamidocephalosporanic acid 7-phenoxyacetamidocephalosporanic acid 7- (2-thienylacetamido cephalosporanic acid to give the following desacetoxycephalosporanic acids, respectively:

7-mandelamidodesacetoxycephalosporanic acid 7-phenylacetamidodesacetoxycephalosporanic acid 7-phenoxyacetamidodesacetoxycephalosporanic acid 7- (Z-thienylacetamido desacetoxycephalosporanic acid.

What is claimed is:

1. In a process of hydrogenating cephalosporanic acids to prepare desacetoxycephalosporanic acids, the improvement wherein a mixture of a cephalosporanic acid and palladium oxide hydrate optionally supported on an inert carrier, in a molar ratio of about 5.5:1 to 1:1, with about 3 to 8 equivalents of base buffered at pH of about 7 to 9.5 is hydrogenated.

2. A process according to claim 1 in which the hydro genation is carried out at about 5 to 15 C.

3. A process according to claim 1 in which 7-aminogenated to give 7-(D-a-aminophenylacetamido)desaoetoxycephalosporanic acid.

4. A process according to claim 1 in' which 7-(D-uaminophenylacetamido)cephalosporanic acid is hydrogenated to give 7-(D-a-aminophenylacetamido)desacetoxycephalosporanic acid.

5. A process according to claim 1 in which palladium oxide hydrate supported on an inert carrier is used.

6. A process according to claim 5 in which the carrier is alpha-cellulose having a particle size of about 20 to 60 microns in average length and about 16 to 20 microns in average thickness.

7. A process according to claim 5 in which the carrier is carbon.

8. A process according to claim 5 in which 7-aminocephalosporanic acid is hydrogenated to give 7-aminodesacetoxycephalosporanic acid.

9. A process according to claim 5 in which 7-(D-aaminophenylacetamido)cephalosporanic acid is hydrogenated to give 7-(D-a-aminophenylacetamido)desacetoxyoephalosporanic acid.

References Cited UNITED STATES PATENTS 3,124,576 3/1964 Stedman 260-243 c NICHOLAS s. RIZZO, Primary Examiner US. 01. X.R. 424-246 (5/69) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,773,76L Dated November 29, 1,273

Inventor(s) Dale W. Blackburn, Robert F. Devermey & John J. Mlynarski It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

1, line 60, antibotic should read antibiotic Column 1, line 62, (cephalhexin) should read (cephalexin) Column 4, cancel lines 31 and 32 and insert the following:

cephalosporanic acid is hydrogenated to give 7-aminodesacetoxycephalosporanic acid. I

Signed and sealed this 23rd day of April 197A.

Attest:

EDWARD M.FLETCHit-JR,,JRa C. MARSHALL DANN Attesting; Officer Commissioner of Patents 

